Suzy and Nan­cy Good­man were more than sis­ters. They were best friends, con­fi­dantes, and part­ners in the grand adven­ture of life. For three decades, noth­ing could sep­a­rate them. Not col­lege, not mar­riage, not miles. Then Suzy got sick. She was diag­nosed with breast can­cer in 1977; three ago­niz­ing years lat­er, at thir­ty-six, she died.

It wasn’t sup­posed to be this way. The Good­man girls were raised in post­war Peo­ria, Illi­nois, by par­ents who believed that small acts of char­i­ty could change the world. Suzy was the big sis­ter — the home­com­ing queen with an infec­tious enthu­si­asm and a gen­er­ous heart. Nan­cy was the lit­tle sis­ter — the tomboy with an out­sized sense of jus­tice who want­ed to right all wrongs. The sis­ters shared make­up tips, dat­ing secrets, plans for glam­orous fan­ta­sy careers. They spent one mem­o­rable sum­mer in Europe dis­cov­er­ing a big world far from Peo­ria. They imag­ined a long life togeth­er — one in which they’d grow old togeth­er sur­round­ed by chil­dren and grand­chil­dren. Suzy’s diag­no­sis shat­tered that dream.

In 1977, breast can­cer was still shroud­ed in stig­ma and shame. Nobody talked about ear­ly detec­tion and mam­mo­grams. Nobody could even say the words ​“breast” and ​“can­cer” togeth­er in polite com­pa­ny, let alone on tele­vi­sion news broad­casts. With Nan­cy at her side, Suzy endured the many indig­ni­ties of can­cer treat­ment, from the grim, soul-killing wait­ing rooms to the mis­takes of well-mean­ing but mis­in­formed doc­tors. That’s when Suzy began to ask Nan­cy to promise. To promise to end the silence. To promise to raise mon­ey for sci­en­tif­ic research. To promise to one day cure breast can­cer for good. Big, shoot-for-the-moon promis­es that Nan­cy nev­er dreamed she could ful­fill. But she promised because this was her beloved sister.

Suzy’s death — both shock­ing and sense­less — cre­at­ed a deep pain in Nan­cy that nev­er ful­ly went away. But she soon found a use­ful out­let for her grief and out­rage. Armed only with a shoe­box filled with the names of poten­tial donors, Nan­cy put her for­mi­da­ble fund-rais­ing tal­ents to work and quick­ly dis­cov­ered a groundswell of grass­roots sup­port. She was aid­ed in her mis­sion by the lov­ing tute­lage of her hus­band, restau­rant mag­nate Nor­man Brinker, whose dynam­ic approach to entre­pre­neur­ship became Nancy’s mod­el for run­ning her foun­da­tion. Her account of how she and Nor­man met, fell in love, and man­aged to achieve the elu­sive ​“true mar­riage of equals” is one of the great grown-up love sto­ries among recent memoirs.

Nancy’s mis­sion to change the way the world talked about and treat­ed breast can­cer took on added urgency when she was her­self diag­nosed with the dis­ease in 1984, a ter­ri­fy­ing chap­ter in her life that she had long feared. Unlike her sis­ter, Nan­cy sur­vived and went on to make Susan G. Komen for the Cure into the most influ­en­tial health char­i­ty in the coun­try and arguably the world. A pio­neer­ing force in cause-relat­ed mar­ket­ing, SGK turned the pink rib­bon into a sym­bol of hope every­where. Each year, mil­lions of peo­ple world­wide take part in SGK Race for the Cure events. And thanks to the more than $1.5 bil­lion spent by SGK for cut­ting-edge research and com­mu­ni­ty pro­grams, a breast can­cer diag­no­sis today is no longer a death sen­tence. In fact, in the time since Suzy’s death, the five-year sur­vival rate for breast can­cer has risen from 74 per­cent to 98 percent.